Autoreactive B- as well as T-lymphocytes are often integral parts of the normal immune system and are not per se pathogenic. Also activation of these autoreactive lymphocytes may in many cases occur without ensuing pathology. In the current paper is discussed two situations whereby unspecific inflammatory stimuli in the form of immunological adjuvants may either by themselves cause arthritis, or may change a non-pathogenetic to a destructive and chronic inflammatory disease.